Rapidly progressive ("crescentic") glomerulonephritis - the majority of glomeruli present
"crescents". Formation of crescents is initiated by passage of fibrin into the Bowman space as a
result of increased permeability of glomerular basement membrane. Fibrin stimulates the proliferation
of parietal cells of Bowman capsule, and an influx of monocytes. Rapid growing and fibrosis of crescents
compresses the capillary loops and decreases the Bowman space which leads to renal failure within weeks
or months. (H&E, ob. x20)